5V, 300mA Step-Down Voltage Regulator D24V3F5

5V, 300mA Step-Down Voltage Regulator D24V3F5

The compact (0.4"×0.5") D24V3F5 switching step-down (or buck) voltage regulator takes an input voltage between 7 and 42 V and efficiently reduces it to 5 V while allowing for a maximum output current of 300 mA. The pins have a 0.1" spacing, making this board compatible with standard solderless breadboards and perfboards.

Overview

These buck (step-down) voltage regulators generate lower output voltages from input voltages as high as 42 V. They are switching regulators (also called switched-mode power supplies (SMPS) or DC-to-DC converters) and have a typical efficiency between 80% to 90%, which is much more efficient than linear voltage regulators, especially when the difference between the input and output voltage is large.

The regulator has short-circuit protection, and thermal shutdown prevents damage from overheating. The board does not have reverse-voltage protection.

The SHDN pin can be driven low (under 0.3 V) to turn off the output and put the board into a low-power state that typically draws 20 μA. The SHDN pin can be driven high (above 2.3 V) to enable the board, or it can be connected to VIN or left disconnected if you want to leave the board permanently enabled.

The input voltage, VIN, should be at least a few volts above VOUT, and you must ensure that noise on your input does not exceed the 42 V maximum. Additionally, please be wary of destructive LC spikes (see below for more information).

LC Voltage Spikes

When connecting voltage to electronic circuits, the initial rush of current can cause voltage spikes that are much higher than the input voltage. If these spikes exceed the regulator’s maximum voltage (42 V), the regulator can be destroyed. In our tests with typical power leads (~30" test clips), input voltages above 20 V caused spikes over 42 V. If you are connecting more than 20 V or your power leads or supply has high inductance, we recommend soldering a 33μF or larger electrolytic capacitor close to the regulator between VIN and GND. The capacitor should be rated for at least 50 V.